Production of compressed air on board aircraft



June 3, 1947. c. RQWASEIGE PRODUCTIONOF COMPRESSED AIR ON BOARD AIRCRAFT Filed May 21, 1942 2 Sheets-Sheet 1 m 0 I m June 3, 1947- 'c. w sEm 2,421,398

PRODUCTION OF C OMPRESSED AIR ON BOARD AIRCRAFT Filed May 21, 1942 '2 Sheets-Sheet 2 A 4 .m-MR ll A 7/4/44 3"! ll? SUfERC/IWRGEK W 3 z 7 m0 0 a y 5 /4// 7 COMP/555501? I mums [mm- MIN/FOLD PROPELLDR Patented June 3, 1947 PRODUCTION OF COMPRESSED AIR N BOARDAIR'CRAFT Charles Raymond Waseige, Rueil, France vested in the Attorney General of the United States Application May 21, 1942,.Serial No. 443,966

In France December 24, 1940 Myinvention relates to improvements in de yices for producing compressed air for the operation of apparatus onboard aircraft.

As is well known, it is necessary for the operation of apparatus on board aircraft that air be supplied at widely different pressures, for both discontinuous and continuous use, and that differences in atmospheric pressure and in air density at different altitudes above the earth must be taken into account, Air pressure producing devices heretofore used for the purpose have been cumbersome, difficult to cool, and, required an excessive amount of power for their operation, as in the case where a single pressure tank having a number of pressure relief devices has been used to supply compressed air at the widely differing pressures required by a similar number of pieces'of apparatus. 7

The primary object of the present invention is to provide a device of the character indicated which reduces or eliminates the above mentioned dimculties and others, by employing at least two air compressors, one of which intakes atmospheric air and feeds the other compressor at a substantially constant absolute pressure, determined by the operation of valving means in the air circuit of the first mentioned compressor, responsive to the altitude of the aircraft.

Because of the controlledsupercharging of the second compressor thus provided,- the'device can supply air at the required pressure regardless of the altitude of the aircraft. .The valving means is preferably arranged in the output side of the air circuit of the first compressor so that the first compressor feeds both the second compressor and that part of the device to which this pressure is suited. The 'valving means' can also be arranged in the suctionsideof the air circuit of the first compressor so as to more or less throttle the air intake of the first compressor. The adjustment of the valving means is preferably controlled by a suitable form of manometric capsul or cartridge.

In a preferred embodiment of the invention the device comprises a third compressor arranged to deliver air at .a higher pressure than that de- 13 Claims. (01. 230-45) vantag'eously be either a pump of the volumetric type or may consist of a supercharger of one of the aircraft engines arranged in advance of the engine carbureter,

' The several air compressors are preferably aligned and. arranged as a self-contained assembly driven by a singleshaft.

' of producing an almost absolute vacuum, it is It is known that heretofore the suction of the low pressure pump has been used for revolving the rotors of gyroscopicinstruments on'board aircraft, the necessary vacuum for the purpose not possible to assure proper operation of such gyroscopic instruments above a, certain altitude. However, in accordance with the present inven: tion, these difficulties are eliminated by operating these instruments with pressure from the output side of the low pressure compressor through a pressure relief means.

Thepresent invention consists also in certain accessories particularly adapted to my novel compressed air supplying device, notably an automatic cock or valve, pressure limiting valves, and the like, so devised as to be combinable with a manometric capsule or cartridge, which can either empty or fill with air at ground atmospheric pressure so that the adjustment of the valves varies in accordance with the altitude of the aircraft. 5 I

Other objects and features of the invention will appear from the following description and the accompanying drawings wherein exemplary embodiments of the invention In the drawings: v Figure 1 is a diagrammatic view of a device or installation in accordance with the present invention; r

Figure 2 is a similar but fragmentary-viewof a, modification thereof; I r Figures 3.to-6 'are vertical'sectional views on a larger scale of several components of the em bodiment shown in Figure 1, comprising theregulating valve of Figure 3,-the regulator of Figure 4, the automatic cock or valve of Figure 5, andthe pressure relief device of Figure 6; Figure 7 is a. fragmentary vertical'section taken through a modification of the valve for limiting the flowpressure delivery pressure; and t .Figure 8' isa diagrammatic representationlof an arrangement-according to the invention in which the aircraft engine carburetor super are set forth.

compressor 3.

The low pressure compressor intakes free atmospheric air and has itsoutput pipe 4 connected to a purifier or scrubber 5 of any suitable type capable of removing. the oil or water particles carried by the air.

The purifier or scrubber 5 is provided at its lower end with a pressure regulating valve 6 pressed by a spring 1 .against its seat. This valve establishes communication between the inner chamber of the purifier and the outside atmosphere through an opening 8 when the pressure in said chamber exceeds a pressure predetermined by the tension of the spring I.

The compresesd air leaves the purifier 6 through a pipe In which divides into a branch pipe H which feeds servo-devices, and'a branch pipe |2 which feeds the medium pressure compressor 2. It is assumed in this case that there are two of such servo devices fed by low pressure, namely, the piping l5 of the de-icing device and the gyroscopes associated with the steering instruments I6. The piping of the de-icing device is fed through a valve l8 comprising a chamber enclosing a closing shutter l9 rockably mounted on a pivot and controlled by suitable means (not shown) so as to close and open without causing any braking efi'ect upon the flow of air therethrough. An electric distributor 20, energized through a rheostat 2|, distributes through the pipes IS the air which must reach the several pneumatic chambers arranged on the leading edges of the wings of the aircraft, the pulsatin of which chambers produces the de-icing effect. The air is supplied to the gyroscopes associated with the steering gear |6 through a pressure regulating valve 22. One illustrative form of such a valve is shown in Figure 3 of the drawings and is hereinafter described.

The medium pressure compressor 2, which is fed by the low pressure generator through the pipe I2, is of usual type and discharges through a pipe 25 (shown in dotted lines), and preferably through a regulator 26, into a reservoir 28. The regulator 26, a preferred form of which is hereinafter described and is shown in Figure 4, provides communication with the outside atmosphere for the delivery pipe 25 whenever the air pressure in the reservoir 28 exceed a predetermined limit. The compressed air in the reservoir 28 supplies the servo devices through the pipe 30' at the medium pressure required for, for example, the operation of the aircraft's brakes, automatic weapons, etc., while the pipe 3| conveys the excess air to the intake of the high pressure compressor 3.

The high pressure compressor 3, thus supplied with air under medium pressure, forces the air under higher pressure through a pipe 34, and preferably through a regulator 35, into a reservoir 36. The regulator 35 isof a type similar to the regulator 26 and establishes communication between the delivery side of the high pressure compressor -3 and the outside atmosphere whenever the pressure in the reservoir 36 exceeds a predetermined limit. The pipe 34 can be advantageously connected through a ipe 38 to a distributor 39 connected in the pipe 3|. A preferred form of distributor 39, shown in as to shut ofl the-upside part of the pipefM-and to establish'commuuication with the outside atmosphere of the inlet side of the'compressor 3 when its output side opened to the atmosphere by the action of the regulator 35. The circuit is restored to normal whenever the pressure is restored atthe delivery pipe 34. Any excessive output of, ;the;medium pressure compressor 2 is thereby avoided when the high pressure compressor is inoperative.

The air underthe highest stage of compression leaves the reservoir 36 through a pipe 36 which supplies the servo-motor operated devices of the aircraft requiring high pressure actuation.

In Figure 1 is shown a means of using the reserve of high pressure air contained in the reservoir 36 for supplying those servo-motor operated devices which require only medium pressure for their actuation. For this purpose, a branch pipe valve 4| is 'manually controlled, its two alternative positions corresponding to interruptions of air flow through the pipes 3| and 46, respectively.

The pressure reducing valve 42, shown in- Figure 6 and hereinafter described, supplies medium pressure air to a pipe 43 in which is connected a' one-way valve 44 of conventional form, permitting the air to flow in only one direction. T 1? pipe 43 is connected to the pipe 3| at a'poirit between the shut-off valve 4| and the reservoir constituted by the compressor used for super? charging the aircraft engine, and be branched off from the intake side of the carbureter, is here shown as comprising a vacuum pump of the volumetric type essentially constituted, as illustrated in Figure 2, of a body or casing and an eccentric rotor enclosed therein and fitted with vanes or blades.

The medium and high pressure compressors 2 and 3, which may be of the centrifugal type, are shown as including pistons and cylinders mounted on a common casting 48, to which the cylinder of the low pressure compressor is secured. The three compressors 2 and 3 are aligned and driven by a common actuating shaft 49, so as to form a self-contained assembly.

As illustrated in Figure 3, the regulating valve 22 comprises a body made up of three parts. The part 50 carries the air inlet union 5|, while the second part 52 is screwed upon the part 50 and comprises substantially a cylindrical tube fitted at its upper end with the air outlet union 53, the third part 54 being screwed upon the part 52, forming a cap fitted upon its upper end.

The part 50 of the regulating valve 22 forms the housingof a disk valve 56, whose seat 51 is situated above it and underneath the union 53. The valve 56 is carried by a sleeve 58 which is urged upwardly by a spring 59. A rod 60, connected to the sleeve 58, is urged by the spring 59 into contact with a projection on a sleeve 6| which is slidably fitted in the tube 52. The lower end of the sleeve 6| is provided with a gasket.

63 tightly applied against the inner wall of the tube 52. A spring 64, accommodated in the sleeve 7 6|, urges the sleeve 6| in a direction corresponding to that in which the valve 56 opens and is' 'i abutted, through the mediiim of a head member 66, with a :membrane 61; carried lby the -iianges shaped third part 54 of the yaive 22,

being, formed in the' said partl. membrane 61 is. of distortjable character and iorms-oneof the walls ofta sealed vacuum chamber Ii9 containing. v a spring which urges the membrane downw wardly, thatjis to say,.in such a direction-as to compress the spring 64; As will be understood,v

the pressurejof the-air flowing, past the valve.

56 presses "on the gasket 63, wherebywhen the air pressure upon the gasket at one side exceeds the atmospheric pressure on its other side plus i the resistance of the spring 64, thesleeve His lifted and closes the valve 56. r s

Reopening 01 this valve takes place in the union 5.3 subsides.

The membrane 61 is distorted by the spring 10 thereby increasing the tensionof the spring 64 when the outside atmospheric pressure diminishes, as when the aircraft reaches altitude above the-earth, so that the force exerted on the sleeve 6i and consequently the limit pressure of the air inside of the union 53 are independent of the altitude or vary in terms of the altitude according to a determined law. Supply of air through the regulating valve 22 to the servomotor oper duct 84 connected to the duct v11 at the upside of the valve 82 leads-to a union 85 which is in free communication with the outside atmosphere. A needle valve 81 housed in the duct 84 is downwardly urged toward its seat by a spring 88. The needle valve 81 is connected to a rod 89 which is pivotally connected to a lever 90, one end of which is pivotally connected in turn to a stationary pin 9|, and the other end to a piston 92 which is subject to the air pressure in the chamber 8| while being urged in the opposite direction by a spring 98. r

A wedge shaped cam 95fixecl to the lever 90 bears against a follower block 91 which is applied against the cam by a spring 96.

It will be understood that normally the compressed air from the generator flows through the regulator between the unions and 16. When.- ever thepressure of this compressed air exceeds the limit determined by the tension of thespring 94, the piston 92 is shifted against the resistance of this spring and rocks the lever 90, whereby the needle valve 81 is lifted from its seat and communication is established between the union 15 and the outside atmosphere, the chamber BI being then shut off from the outside atmosphere by the valve 82. By cooperating with the cam 95, the follower block 91 quickly breaks the balance when the lever 90 is rocked. I

Thereafter, whenever. the pressure prevailing in the chamber 8| returns to normal the regulator operates in the reverse direction and reestablishes communicationbetween the ducts 11 and 18.v

. In Figure 5 is shown a formof distributor 39 wherein its body Hi0 communicates laterally by e. action of the spring 64 whenever the air pressure I pressure relief device or pressure reducer,-

thrcugh a union m with the upside portion or the pipe 3|, and through-fa union I02 with the wnsid -Pa tial 1; the. PIPHL. t a ct on 0. air 4. 10. rli ing indicated by arrows; and one jerid of thebody l,00 llsconnected by; a union, I03 with v the: pipe ,38, ..which is connected to the eu-very side otthe pressure compressor and v,thje

cted by a union";

otheriend t he body is'cone m with the outsideatmo'sphre; 1 1

, e body Ion is termed wlthiabylindrical porj 'tion I06 which extends between the unions I03 and IM and with a pair of annular seats"l06and' I01, respectively, located onfoppositesides of the inner end of the union or nipple I02: A fv'alv'e I08 is slidably mounted in the" cylindrical portion'l05 and carries a gasket'll09 havingja convexity ram ing the union I03. ,This gasketis'elastically applied by a washer 0 against "the walls of the cylindrical portion I05.

- The slide 'valve I08 is further provided with a disk valve II 2 arranged 'to cooperate with the two seats I06 and I01. The valve H2 is urged .toward the seat I06 by a weighted spring H4.

When the high pressure compressor delivers air,

the air pressure, acting upon the gasket I09 counterbalances the action of the spring II4 upon the slide valve I00, whereby the valve 2 is forced against the seat I01. The medium pressure air can then flow freely between the unions IN and I02. Howevenwhen, because of the operation of the regulator 35 the high pressure compressor 3 discharges into the outside atmosphere, the pressure acting on the gasket I09 drops, whereupon the sprimg I I4 shifts the slide valve I08 and engages the valve II2 with the seat-I06,

thereby shutting ofi the unions IOI and I02 front each other, while establishing communication between the union I 02 and the high pressure compressor inlet and the outside atmosphere through the union I04.

In Figure 6 is shown a desirable form-for the comprising a body or casing I20 communicating through a union I22 with the high pressure air inlet and through a union-I23 with the outlet of the relief air. Both unionsor nipples arein communication by means of a port I25 formingthe seat of a shut off valve I26. A spring I21 urges sion I30 and is urged by a spring I33 toward the valve I26 which carries a headed stem I34 aligned with the sleeve. It will be understood that with this arrangement the valve I26'is normally held closed, and opens only when a push is exerted by the sleeve I32 upon the headed stem I34 as the'air pressure prevailing in the union I33 drops below a predetermined level. TheIadjustment of the tension of the spring I33 may be under thecontrol of a manometric cartridge.

It is advantageous, generally speaking, 0 maintain constant; regardless of the altitudeof the aircraft, the absolute delivery pressure of the low pressure compressor; or; alternately, to cause said pressure to change with changes in altitude of the aircraft, in accordance with a fixed law.

For this purpose the arrangement shown in Figure '7 has a spring 1, associated with the valve 6 of the air purifier or scrubber, with whizh may be combined a closed manometric cartridge- I40 containing air'at atmospheric pressure, such as the outside atmospheric air diminished in pres sure due to the altitude of the aircraft;

In the embodiment of the invention shown ,in Figure 2, in which the low pressure compressor or generator I serves only for feeding the medium pressure or generator 2, the manometric cartridge controls a damper I44 movable in a casing connected to the suction pipe I' of the low pressure compressor I. The cartridge is enclosed in a tight casing I45 communicating with the delivery pipe I of the low pressure compressor. When the output'of this compressor shows a tendency to increase in the casing I45, the resulting action of the cartridge I40 causes the intake of atmospheric air .intothe compressor to be throttled. Similarly, when the pressure in the casing drops, the cartridge opens the damper I so as to permit an increase of air intake by the compressor I. Because of this arrangement, the pressure at which the compressed air is delivered remains constant.

While I have described and shown herein preferred embodiments of my invention, it will be apparent to those skilled in the art that various changes and modification may be made therein withoutdeparting from the spirit and scope of my invention.

What I claim is:

1. In a system for the production of compressed air on aircraft, at least two compressed air generators, including a first generator and a second generator, a connection between the outlet of the first generator and the intake of the second generator to feed the second generator with air under greater than atmospheric pressure, the intake side of the first generator being open to the atmosphere, and manometric valving means arranged in the circuit of air flowing through the first generator in a manner to determine the pressure at which the second generator is fed in accordance with the altitude of the aircaft.

2. A system' for the production of compressed air on aircraft, according to claim 1, wherein said connection includes an automatic valve having means connected to the output side of the second generator and arranged to automatically establish communication between the intake side of the second generatorand the outside atmosphere while shutting off such communication with said first generator responsive to a drop in pressure of the output of the second generator.

3. In a system for the production of compressed air on aircraft, at least three compressed air generators, including low pressure, medium pressure, and high pressure generators, a connection between the outlet side of the low pressure generator and the intake side of the medium pressure generator to feed the medium pressure generator withair under greater than atmospheric pressure, the intake side of the low pressure generator being open to the atmosphere, manometrically controlled valving means in the circuit of air flowing in the low' pressure generator and arranged to determine the'pressure at which the medium pressure generator is supplied with air, a. connection between the oulet side of the medium pressure generator and the intake side of the high pressure generator, and a service outlet on the last mentioned connection.

4. A system for the production of compressed air on aircraft, according to claim 3,wherein a reservoir is connected to the output of the high pressure generator for charging thereby, and

wherein are comprised a pressure relief device. means connecting said device with the portion of the'system to which the outputpf the'medium pressure generator is suited, and with said reservoir, and a shut-off valve connected both in-the connection-feeding the high pressure generator and in the last mentioned'connecting means, said shut-01f valve being arranged to open one or the other of said connections.

5. In apparatus of the character described for supplying compressed air on board aircraft, the combination of, a. first compressor means to deliver air to a first pressure system, a second compressor means to receive air from said first pressure system and deliver air at a higher pressure to a second pressure system, valve means to effect connection to and disconnection of the intake of said second compressor means from ,said first pressure system and to simultaneously control the connecting of the outlet of said second compressor means to the intake of said second 1 compressor means, and means responsive to the pressure in said second pressure system to control the operation of said valve means.

6. Apparatus as described in claim 5 wherein said control means comprises, means constituting a valved connection between the outlet of said second compressor means and said second pressure system, means responsive to the pressure in said second pressure system to open the outlet of aid compressor means to the atmosphere, and means responsive to a drop in pressure at the outlet of said second compressor means to operate said valve means in a manner to disconnect the intake of said second compressor means from said first pressure system and simultaneously to establish communication between the outlet and the intake of said second compressor means.

7. Apparatus as described in claim 5 wherein pressure reducing means connects said second pressure system to said first pressure system.

8. In a system for the production of compressed air on aircraft having an engine cornprising a, carbureter and a supercharger therefor, said supercharger being connected at the output side of the carbureter and having an air intake open to the atmosphere, said supercharger constituting a first compressed air generator, at least one other compressed air generator, a supply connection between the output side of the first generator or supercharger and the intake side of the second generator, a manometrically controlled relief valve arranged in said supply connection so as to determine the supply pressure to the second generator in accordance with the altitude of the aircraft.

-9. A plant for supplying compressed air to operate utilization means in aircraft or the like, said plant comprising at least two compressed air generators, a suction conduit connected to the intake of the first generator, a second conduit leading from the output side of the first generator to the intake of the second generator to supply-said second generator with air at above atmospheric pressure, valving means arranged in said suction conduit for variably controlling the flow of air into the first generator, and control means for said valving means comprising a manometric 9 I capsule subject to the pressure prevafling in said conduit.

10. In a system for the production of compressed air on aircraft, at least two compressed air generators, including a first generator and a second generator, the intake side of the first generator being open to the atmosphere, a supply connection between the outlet side of the first generator and the intake side of the second generator, a manometricaliy controlled relief valve arranged in said supply connection so as to determine the supply pressure to the second generator in accordance with the altitude of the aircraft.

11. A system, according'to claim 1, wherein said valving means includes resilient control means arranged to maintain the supply pressure to the second generator substantially constant in absolute value.

12. A system, according to claim 10, wherein said relief valve comprises elastic means urging the valve toward closed position and a manometric capsule arranged to adjust, the tension of said elastic means in response to the atmospheric /pressure at the altitude of flight.

13. In an installation for the production of compressed air on board aircraft or the like, a source of compressed air, a compressed air generator, an automatic distributor valve comprising a body, a conduit connecting said source of compressed air with a part of said body, another conduit connecting another part of said body with the intake of said generator whereby said generator can be supplied with air under greater than atmospheric pressure, a further conduit connecting another part of said body with the output of said generator, said body being provided with an opening to the atmosphere, and a, spring loaded valve element in said body arranged to occupy either of two extreme positions in response to the output pressure of the generator, one of said positions establishing communication between the intake of the generator and with the atmosphere while shutting off communication between the intake of the generator and saidsource ofcompressed air, and the other position shutting ofl communication with the atmosphere while providing communication between the intake of the generator and said source of compressed air.

CHARLES RAYMOND WASEIGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

